Studies within the project were directed at the analysis and synthesis of peptides with infrequently seen structural features and at proteins: (a) synthesis of precursors of rings A and B of nisin, a peptide with alpha,beta-unsaturated and thioether amino acids; (b) relationship between minimum structural requirements and biological action of peptides patterned on nisin on neonatal and neoplastic tissue; (c) synthesis of gramicidin A and analogs of the gramicidins A, B, and C; correlation of structural components with transmembrane channel formation and ion transport in lipid bilayers; native gramicidin A inhibits the growth of tumor (L-1210) cells; (d) synthesis of peptides with agonistic and antagonistic effects on fertility regulating hormones - hyperactive releasing factors for luteinizing hormone; (e) application of DEHYDROALANINE RESINS to the synthesis of peptide amides; (f) synthesis enkephalin analogs with mixed agonist/antagonist properties; (g) synthesis and modification of a pentapeptide with chemotactic and anti-chemotactic characteristics; (h) structural studies on CINNAMYCIN and DURAMYCIN; (i) development of new technique in peptide synthesis, amino acid analysis, and the NONENZYMATIC fragmentation of peptides and proteins. BIBLIOGRAPHIC REFERENCES: Gross, E.: Nonenzymatic fragmentation of proteins and its application to molecules with rarely seen amino acids: biosynthesis and phylogentic aspects. Fox, J.L., Deyl, Z., and Beazej, A. (Eds.): Protein Structure and Evolution, New York, New York, M. Dekker, Inc., 1976, pp.69-90. Chen, H.C., Hodgen, G.D., Matsuura, S., Lin, L.J., Gross, E., Reichert, L.E., Birken, S., Canfield, R.E., and Ross, G.T.: Evidence for a gonadotropin from nonpregnant subjects that has physical, immunological, and biological similarities to human chorionic gonadotropin. Proc. Natl. Acad. Sci. 73:2885-2889, 1976.